Deformable Bullnose Energy Absorbing System (BEAS). Report 2: Head-On Impact with a Deformable BEAS and Introducing a Collapsible Arch

摘要

An impact between a tow and the bullnose of a lock approach wall can result in the tow breaking up with loose barges moving out of control toward the lock or navigation dam with serious consequences. Project operations can be severely affected or even shut down. The loose barges can cause a high safety risk to personnel involved and if the navigation pool is lost or the lock is damaged, significant economic impacts may result. This Technical Report discusses the second stage of research into the development of a Deformable Bullnose Energy Absorbing System (BEAS) impact structure that would help reduce or prevent lashing failures and loose barges due to an impact between a tow and a lock approach wall bullnose. In simulations, the first improvement for limiting approach velocity to maintain barge integrity was achieved by the proper selection of lashing layout. The second improvement was achieved by the introduction of the Deformable BEAS. For a head-on collision between a three by five barge train at 3.3 feet per second and a rigid bullnose, barge train integrity is lost. For the same barge train, this report shows that the addition of an impact nosing with double stacked, soft base isolators for a Deformable BEAS extends the maintenance of barge train integrity to 4.5 feet per second. For a head-on collision between a three by four barge train at 3.0 feet per second and a rigid bullnose,barge train integrity is lost. For the same barge train, this report shows that the addition of the collapsible front arch to an impact nosing with double stacked, soft base isolators for a Deformable BEAS extends the maintenance of barge train integrity to 4.7 feet per second. These results imply that the addition of other innovative energy absorbing features could allow for even higher approach velocities.